PROJECT SUMMARY This R21 project will use potent chemical inhibitors of bacterial quorum sensing to develop new materials and explore innovative approaches to the attenuation of bacterial infections in skin wounds. These objectives will be accomplished by the pursuit of two focused and integrated Aims: (1) development of polymer-coated wound dressings that promote the local release of synthetic quorum sensing inhibitors that target virulence factor and biofilm production in the common and notorious human pathogen Staphylococcus aureus, and (2) characterization of the ability of these dressings to attenuate bacterial load and promote the healing and repair of wounds using a mouse model of bacterial skin infection. Bacterial infections pose persistent and costly threats in myriad health settings. These problems are now urgent because the current arsenal of conventional antibiotics has been almost completely depleted by the emergence of drug-resistant bacterial strains. The importance of the growing resistance threat and its potential impacts on society are nearly impossible to overstate; new approaches to treat bacterial infections and move beyond conventional strategies are desperately needed. One promising alternative approach to prevent unwanted bacterial colonization in wounds that does not involve killing bacterial cells is to target non-essential pathways that control virulence in bacteria. Such non- bactericidal `anti-virulence' strategies can circumvent resistance and represent a potential paradigm shift for the clearance of biofilms and the treatment of infections. Bacterial cell-cell signaling (or `quorum sensing', QS) is one of the most attractive targets in the emerging anti-virulence field because it controls many of the primary mechanisms that underlie bacterial infection, including toxin production, adhesion, and biofilm formation. Our laboratories have developed several of the most potent chemical inhibitors of QS currently known. These compounds and their ability to strongly inhibit virulence in S. aureus are the focus of this proposal. The proposed work is based on two broad propositions: (i) that inhibition of QS in bacteria can prevent undesirable behaviors that lead to infection in vivo, and (ii) that inhibition of QS in surface-associated bacteria can be accomplished most effectively through the design of surfaces and interfaces containing agents that target QS pathways. This innovative and cross-disciplinary research seeks to explore these new ideas and test hypotheses that will create a foundation for the development of anti-virulence treatments in the specific and clinically relevant?and increasingly urgent?context of preventing infections in skin wounds through the design of novel wound dressings that prevent bacterial QS and virulence. Our research plan unites a team of four established and actively collaborating investigators at the UW?Madison with a unique mix of expertise in quorum sensing, chemical biology, materials engineering, microbial pathogenesis, and clinical wound care to demonstrate the feasibility of this new, materials-focused anti-virulence approach.